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Retired Moderator
Joined: 10 Apr 2015
Posts: 6218
Given Kudos: 136
4^(2x)
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Updated on: 28 Jul 2016, 02:26
Updated on: 28 Jul 2016, 02:26
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Question Stats:
73% (00:31) correct
26% (00:47) wrong based on 137 sessions
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Quantity A |
Quantity B |
4^(2x) |
16^x |
A)The quantity in Column A is greater.
B)The quantity in Column B is greater.
C)The two quantities are equal.
D)The relationship cannot be determined from the information given.
Note: These questions are designed to help students master the quantitative comparison questions on our site: https://www.greenlighttestprep.com/modu ... comparison
Originally posted by GreenlightTestPrep on 27 Jul 2016, 15:14.
Last edited by Carcass on 28 Jul 2016, 02:26, edited 1 time in total.
Last edited by Carcass on 28 Jul 2016, 02:26, edited 1 time in total.
Adding the tags
Retired Moderator
Joined: 10 Apr 2015
Posts: 6218
Given Kudos: 136
Re: 4^(2x)
[#permalink]
Updated on: 30 Jul 2016, 05:57
Updated on: 30 Jul 2016, 05:57
GreenlightTestPrep wrote:
Quantity A |
Quantity B |
4^(2x) |
16^x |
If you're not sure where to start, you can always start with PLUGGING IN NUMBERS.
Let's start with an easy value for x. How about x = 0
We get:
Quantity A: 4^(2x) = 4⁰ = 1
Quantity B: 16^x = 16⁰ = 1
Okay, the quantities are EQUAL
At this point, we know the correct answer is C or D
Now try some other value for x.
How about: x = 1
We get:
Quantity A: 4^(2x) = 4² = 16
Quantity B: 16^x = 16¹ = 16
The quantities are still EQUAL
Let's try x = -1
We get:
Quantity A: 4^(2x) = 4ˉ² = 1/4² = 1/16
Quantity B: 16^x = 16ˉ¹ = 1/16
The quantities are still EQUAL
Let's try one more value for x. How about x = 2
We get:
Quantity A: 4^(2x) = 4⁴ = 256
Quantity B: 16^x = 16² = 256
The quantities are still EQUAL
At this point, we might be reasonably convinced that the two quantities will always be equal. So, you might submit this as the correct answer and move on.
In my next post, I'll show you why the correct answer is C
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Originally posted by GreenlightTestPrep on 28 Jul 2016, 10:18.
Last edited by GreenlightTestPrep on 30 Jul 2016, 05:57, edited 1 time in total.
Last edited by GreenlightTestPrep on 30 Jul 2016, 05:57, edited 1 time in total.
Retired Moderator
Joined: 10 Apr 2015
Posts: 6218
Given Kudos: 136
Re: 4^(2x)
[#permalink]
28 Jul 2016, 10:22
28 Jul 2016, 10:22
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Bookmarks
GreenlightTestPrep wrote:
Quantity A |
Quantity B |
4^(2x) |
16^x |
NOTE: If you've just begun preparing for the GRE, you might not yet be familiar with the laws of exponents. Nevertheless, here's another approach.
Take 16 in Quantity B and rewrite it as 4²
We get:
Quantity A: 4^(2x)
Quantity B: (4²)^x
Now apply the POWER OF A POWER Law to Quantity B to get:
Quantity A: 4^(2x)
Quantity B: 4^(2x)
At this point can be certain that the two quantities will always be equal
Answer:
Show: ::
C
RELATED VIDEO
